Cetacean protection system

ABSTRACT

An embodiment according to one or more aspects of the present disclosure for conducting a marine survey includes towing a survey spread comprising a plurality of receivers and an energy source along a selected course; emitting a signal from an energy source; receiving data from the plurality of receivers; detecting a cetacean from the received data; positioning the detected cetacean; limiting contact with the detected cetacean; and conducting a marine survey.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 61/097,803, filed Sep. 17, 2008.

TECHNICAL FIELD

The present invention relates in general to detecting and determiningthe position of marine mammals and more specifically to protectingmarine mammals from man-made energy sources (e.g., acousticdisturbances).

BACKGROUND

In an ever increasing frequency man and marine mammals are crossingpaths. It is therefore a desire to mitigate any harmful exposure of themarine mammals to man's activities. One source of concern for marinemammals is marine survey operations. Heretofore, various systems havebeen proposed and utilized to identify and position marine mammals.However, these systems are often undesirable in construction, logisticalrequirements in addition to providing only the most rudimentaryfunctionality.

There is a continuing desire to provide and display real-timeinformation to mitigate the harm or perceived harm to marine mammalsfrom marine survey operations. There is a desire to identify safety orprevention zones for the marine mammals. There is also a desire toprovide efficient survey operations while limiting contact with marinemammals.

SUMMARY

An embodiment according to one or more aspects of the present disclosureof a monitoring system for marine mammal detection integrated into amarine survey system includes an array of receivers; an energy sourceemitting a signal for conducting marine surveys; and a processing unitadapted to receive data from the array of receivers to detect a cetaceanvocalization.

An embodiment according to one or more aspects of the present disclosureof a method for limiting contact with marine mammals during marinesurvey operations comprises conducting a seismic survey; identifying aprevention zone relative to the seismic survey; detecting the presenceof a cetacean; and limiting contact with the prevention zone.

An embodiment according to one or more aspects of the present disclosurefor conducting a marine survey includes towing a survey spreadcomprising a plurality of receivers and an energy source long a selectedcourse; emitting a signal from an energy source; receiving data from theplurality of receivers; detecting a cetacean from the received data;positioning the detected cetacean; limiting contact with the detectedcetacean; and conducting a marine survey.

The foregoing has outlined some of the features and technical advantagesof the present invention in order that the detailed description of theinvention that follows may be better understood. Additional features andadvantages of the invention will be described hereinafter which form thesubject of the claims of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and aspects of the present inventionwill be best understood with reference to the following detaileddescription of a specific embodiment of the invention, when read inconjunction with the accompanying drawings, wherein:

FIG. 1 is a plan view of an embodiment of a cetacean protection systemof the present integrated in a marine survey system; and

FIG. 2 is an elevation view of an embodiment of the cetacean protectionsystem of the present invention.

DETAILED DESCRIPTION

Refer now to the drawings wherein depicted elements are not necessarilyshown to scale and wherein like or similar elements are designated bythe same reference numeral through the several views.

Reference is made to a towed marine seismic survey, where one or severalstreamers are towed behind a vessel with one or more sources towedbehind the same and/or another vessel. The seismic streamers may beseveral thousand meters long and contain a large number of sensors,which are distributed along the length of the each seismic streamercable. Reference may be made to the in-line direction as the directionin the horizontal plane parallel to the streamer(s). A Cartesiancoordinate system will also be used where the in-line direction isreferred to as the x-direction. Conversely, the cross-line direction maybe referred to as the direction in the horizontal plane perpendicular tothe streamer(s). In the Cartesian coordinate system, the cross-linedirection is referred to as the y-direction.

The sources generate seismic waves, which propagate into the geologicalformations creating pressure changes and vibrations along their way.Changes in elastic properties of the geological formation scatter theseismic waves, changing their direction of propagation and otherproperties. Part of the energy emitted by the sources reaches theseismic sensors. Some seismic sensors are sensitive to pressure changes(hydrophones), others to particle motion (e.g., geophones), andindustrial surveys may deploy only one type of sensors or both. Inresponse to the detected seismic events, the sensors generate electricalsignals to produce seismic data. Analysis of the seismic data can thenindicate the presence or absence of probable locations of hydrocarbondeposits. Similarly, electromagnetic (EM) surveying can use EM sourcesand receivers. One type of EM surveying is referred to as controlledsource EM surveying (CSEM), in which an EM transmitter is used togenerate EM signals that are propagated into the subterranean structure.Subterranean elements reflect the EM signals, with the reflected EMsignals received by the EM receivers.

For the case of multi-component seismic sensors, each sensor may becapable of detecting a pressure wavefield and at least one component ofa particle motion that is associated with acoustic signals that areproximate to the multi-component seismic sensor. Examples of particlemotions include one or more components of a particle displacement, oneor more components (inline (x), crossline (y) and vertical (z)components of a particle velocity and one or more components of aparticle acceleration. An example of a commercial multi-component systemdesigned for ocean-bottom (also known as seabed) applications isWesternGeco's Q-SEABED system.

Depending on the particular embodiment, the multi-component seismicsensor may include one or more hydrophones, geophones, particledisplacement sensors, particle velocity sensors, accelerometers,pressure gradient sensors, or combinations thereof. For example, inaccordance with some embodiments, a particular multi-component seismicsensor may include a hydrophone for measuring pressure and threeorthogonally-aligned accelerometers to measure three correspondingorthogonal components of particle velocity and/or acceleration near theseismic sensor. It is noted that the multi-component seismic sensor maybe implemented as a single device or may be implemented as a pluralityof devices, depending on the particular embodiment. A particularmulti-component seismic sensor may also include pressure gradientsensors, which constitute another type of particle motion sensors. Eachpressure gradient sensor measures the change in the pressure wavefieldat a particular point with respect to a particular direction. Forexample, one of the pressure gradient sensors may acquire seismic dataindicative of, at a particular point, the partial derivative of thepressure wavefield with respect to the crossline direction, and anotherone of the pressure gradient sensors may acquire, at a particular point,seismic data indicative of the pressure data with respect to the inlinedirection.

FIG. 1 is a schematic, plan view of an embodiment of a cetaceanprotection system generally denoted by the numeral 10. In theillustrated and described embodiment, system 10 is passive cetaceanmonitoring system integrated with a marine survey system (e.g.,electromagnetic surveying, seismic surveying). Some examples of marinesurvey systems that may be utilized in whole or in-part for cetaceandetection are disclosed in: U.S. patent application Ser. No. 12/132,592;U.S. Pat. Nos. 7,466,625; 7,426,439; 7,400,552; 6,684,160 and 5,351,218;and U.S. Patent Application Publication Nos. 2009/0141587; 2009/0003132;2008/0267010; 2008/0186804; 2008/0144442; 2008/0008037; 2007/0025182 and2006/0246654; all of which are incorporated herein by reference. Onetype of EM surveying is referred to as controlled source EM surveying(CSEM), in which an EM transmitter (e.g., source) is used to generate EMsignals, with the reflected EM signals received by the EM receivers.

In some embodiments system 10 may position (e.g., locate) the detectedcetacean for example, and without limitation, by beam-forming. System 10may utilize vector sensors for detecting and/or position the cetaceans.Positioning may comprise determining a location relative to a preventionzone, determining a distance (e.g., range) to the detected cetaceanand/or determining a direction to the detected cetacean from a selectedlocation. In some embodiments, system 10 can detect, classify, position,and track marine mammals relative to the marine survey system. System 10may provide data as to the survey (e.g., energy) source level that themarine mammal may have been, or will be, exposed from the encounter withthe survey operations. Marine mammals are defined generally herein ascetaceans and include without limitation whales, porpoises, dolphins,sea otters, sea lions, seals, and walruses.

System 10 comprises a survey system including a vessel 12, a towedstreamer 14, a survey source 18, and a processing unit 20. Vessel 12commonly tows a plurality of streamers 14 laterally space from oneanother to form a spread 22 for conducting the marine survey. Eachstreamer 14 commonly includes a plurality of receivers 16, which mayinclude without limitation vector wavefield sensors. Examples ofreceivers 16 include without limitation, accelerometers, hydrophones,geophones, electromagnetic receivers, particle motion sensors, pressuregradient sensors and combinations thereof. Receivers 16 may be singlesensor receivers. In some embodiments, one or more of receivers 16 maybe grouped formed. Examples of some group formed, and multi-componentstreamers, are disclosed in U.S. Pat. Nos. 6,684,160 and 5,351,218 andin U.S. Patent Application Publication No. 2009/0003132, which areincorporated herein by reference.

Each streamer 14 may also include a global positioning (GPS) unit 24.GPS unit 24 may be carried by a buoy and may be combined with variouselements and systems such as and without limitation a guidance systemand transceiver. Although not illustrated specifically in FIG. 1, it isunderstood that survey spread 22 may include a ranging and positioningsystem that may include pingers and dedicated ranging receivers.

In the depicted embodiment, system 10 includes a survey source 18 (e.g.,source array) towed by vessel 12. Survey source 18 may include varioustypes of energy sources including without limitation airguns andelectromagnetic sources. In the depicted system, source 18 includes oneor more source receivers 26 which may include, without limitation,vector wavefield sensors, hydrophones, geophones, accelerometers,positioning hydrophones, near field hydrophones (NFH), particle motionsensors, pressure gradient sensors, electromagnetic sensors andcombinations thereof. Source 18 and source receivers 26 may bepositioned on a streamer that is separate from the survey streamer. Insome embodiments, one or more receivers 16, 26 may, for example, bepositioned on a streamer that is towed behind the source streamer andahead of the survey streamer. It is also recognized that the surveystreamer and the source streamer may be towed behind separate vessels.

According to one or more aspects of the present disclosure, system 10may detect and position cetaceans 28 such that remedial actions may betaken to limit and/or preclude exposure of the cetacean to a preventionzone, generally denoted by the numeral 30. According to one or moreaspects of the present disclosure, system 10 may determine (e.g.,define) prevention zone 30, provide remedial actions to maintain adefined prevention zone, and/or implement actions to maintain theprevention zone. For example, prevention zone 30 may be defined as anarea relative to a portion of the survey, such as source 18 for example.Prevention zone 30 may include one or more areas, or subzones.Prevention zone 30 may be defined in terms of areas in which it isdesired to exclude the cetacean and/or to an area in which exposure ofthe cetacean is to be limited (e.g., time of exposure). Preventionzone(s) 30 may be defined statically (e.g., a set geographic boundary)and/or dynamically (e.g., associated with operational factors,parameters, characteristics). System 10 may provide remedial steps oroptions for maintaining the prevention zone, for example to exclude thepresence of the cetacean, limit the time of exposure, etc.). System 10may implement actions to maintain the prevention zone. For example,according to one or more aspects of the present disclosure remedialactions may include, without limitation, altering the course of theseismic survey, ceasing seismic operations, and/or changing operationalparameters such as the frequency and/or amplitude of the “shots” (e.g.,sources 18).

Prevention zone 30 may be defined in various manners including, withoutlimitation, by real and/or perceived effects of operations on cetaceans(e.g., acoustic effects, pressure effects, physical impacts), byregulation (e.g., government regulation), risk of physical damage to thecetacean and/or equipment, and/or environmental factors. For example,the United States Mineral Management Service requires what is termed asan exclusion zone of 500 meters for a water depth of 300 meters. Thisregulated exclusion zone is statically defined and does not take intoconsideration the actual operational parameters or characteristics, suchas the frequency and amplitude of source 18 shots. According to one ormore aspects of the present disclosure, prevention zone(s) may bedefined relative to operational characteristics of the seismic surveyand the criteria for precluding or limiting exposure of the cetacean.For example, according to one or more aspects of the present disclosurethe acoustic level (e.g., energy level) associated with source 18 shotsin a particular survey may be utilized to define the prevention zone(s).Prevention zones 30 that are associated with operational parameters maybe referred to as dynamic prevention zones. In other words, by alteringone or more operational parameters of the survey the scope or boundariesof the prevention zone may be dynamically altered (e.g., in real time)so that the concerns for the cetacean are addressed as well aspermitting the survey to continue.

Refer now to FIG. 2 wherein an elevation view of a system 10 isprovided. Survey streamers 14 traditionally include streamer receiver 16arrays and sets (e.g., arrays) of energy sources 18 (e.g., airguns, EMsources) as the survey source. The survey source 18 may emits (e.g.,shoots) a signal (e.g., an acoustic impulse) with a frequency contentfrom a few hertz to several kilohertz even though the survey band isoften not more than about 128 Hz. Commonly each survey source 18 is setto provide an acoustic output sufficient to obtain deep penetration intothe ocean floor 32. The signal strength may be, for example, greaterthan 220 dB rel 1 micro Pascal and may be seen as a threat to marinemammals in that it might disrupt their behavior and interfere with theirability to locate food and to reproduce.

Refer now to FIG. 2 wherein one embodiment of a method of protectingcetaceans 18 is described. In a first step, cetacean 28 is detected. Insome embodiments, the input is being continuously recorded from singlesensor receivers 16 and/or 26, wherein a cetacean 28 vocalization 34 isidentified (e.g., captured). In some embodiments, input may be providedthrough shot based recordings, for example, recordings associated withactivation of source 18. Detecting vocalization 34 includes identifyingor classifying a received signal as a cetacean 28. Detecting may furtherinclude classifying the particular genus or species of cetacean 28 thatis detected.

System 10 may provide locating the position of cetacean 28. In oneexample utilizing single sensor receivers 16 and/or receiver 26,cetacean 28 is positioned using data received from a plurality of thesingle sensor receivers using beam-forming techniques. Positioning mayinclude determining the position relative to a prevention zone or thelike, determining a range to cetacean 28 and/or a range and direction tocetacean 28 from a selected location. Vector sensor technology may beutilized for capturing, detecting and/or positioning of cetaceans 28.Streamers 14 may be group formed.

In an example of system 10, single sensor receivers 16, 26 may beutilized for the detection, classifying and tracking of a cetacean 28.Typically streamer receivers 16 utilize a sampling frequency ofapproximately 500 Hz or 100 Hz for seismic acquisition operations forexample. Utilizing a plurality of single sensor receivers 16, system 10may receive inputs at a higher sampling frequency compared to commonsurvey sampling frequencies, for example, of 1000 Hz and above, and anexemplary embodiment in the range of 1 to 100 kHz. In some embodimentsof system 10, receivers 16 and/or receivers 26 may be grouped orconfigured in selected locations within spread 22 for the purpose ofdetecting and/or positioning the marine mammals. In some embodiments, abandwidth may be assigned to a specific segment of streamers 14 (e.g.,spread 22) for example to capture more high frequency data. Cetacean 28may be detected by identifying a vocalization in the input (e.g., datarecorded by receivers 16 and/or receivers 26). The vocalization may beidentified in a detection sampling frequency. The detection samplingfrequency may be a predetermined sampling frequency. For example, thewave field may be sampled at one or more frequencies, referred togenerally herein as detection frequencies. In some embodiments thedetection sampling frequency may be a higher frequency or a lowerfrequency than the frequency utilized for the marine survey operations,and/or the detection frequencies may be within the survey frequencyrange. In some examples, the input may be monitored at a detectionsampling frequency to detect a cetacean 28, for example from itsvocalizations.

Single sensor source receivers 26 may be utilized to detect and to trackcetaceans 28. Sampling frequencies of source receivers 26 may be set forexample, and without limitation, at about 1000 Hz to several hundredkilohertz. A higher sampling frequency is possible due to sourcereceivers 26 receiving less survey data volume relative to streamerreceivers 16. Additionally, source receivers 26 may be provided atdifferent depths in the water column and therefore may provide moreaccurate positioning of cetacean 28 in particular in regard to depth ofcetacean 28. For example, source receivers may be towed at depth levelsabove, below, and/or equal to source 18.

In one example a plurality of single source receivers are set at asampling frequency of about 1 to 100 kHz. These selected receivers arecontinuously recording data and transmitting the data to processor 20.Continuous data recording is utilized to ensure the cetacean sound isrecorded. It is understood that although processing unit 20 isillustrated on vessel 12, it may be located remote from vessel 12.Processing unit 20 may include an electronic module having a database ofcetacean vocalizations. In some embodiments, comparison and analysis ofthe received signals with the known frequencies, characteristics, andpatterns of cetacean vocalizations may be utilized to classify thereceived signal as a cetacean 28. It is also often desired to classifythe cetacean 28. Methods for classifying cetacean 28 may includespectral analysis, frequency-time analysis, higher order spectralcomponents, and statistical properties.

Once a cetacean 28 is detected, processing unit 20 may begin to positionand/or to track cetacean 28. Various means may be utilized forpositioning and tracking including, without limitation, time of arrivaland beam forming techniques. It is noted that system 10 may include aplurality of single sensor receivers to utilize beam-forming techniquesto localize cetacean 28. Examples of vector sensor technology aredescribed, for example, in U.S. Pat. Nos. 7,466,625 and 7,426,439, whichare incorporated herein by reference.

In some embodiments, positioning of cetacean may not be limited tolocating a specific geographic position of cetacean 28 but be related todetermining a range to cetacean 28, for example, the distance betweensource 18 and cetacean 28, or the location of cetacean relative to aprevention zone. Processing unit 20 may provide a visual display and/oran auditable signal if the tracked cetacean 28 is positioned in and/oris approaching a prevention zone 30. Processing unit 20 may provideoption to minimize the disruption to the survey operations. For example,processing unit 20 may provide alternative courses for “shooting” theline or for shooting subsequent lines; alternative amplitude and/orfrequencies emitted by source 18 to avoid affecting cetacean 28; and/orceasing operations until the detected cetacean has cleared theprevention zone.

In one embodiment, source receivers 26 provide for utilization of veryhigh sampling rates as well as continuous data recording. Therefore, agood resolution can be obtained in the desired frequency domain. Forexample, survey source 18 may be 15 meters long and include 2 to 4 subarrays separated by 5 to 10 meters. Each one of the sub arrays mayinclude several source receivers 26. Thus, a 3-dimensional array of datato determine the range and heading, as well as the depth, of cetacean 28may be obtained.

As noted, system 10 may include multi-component and/or group formedstreamers 14. In some embodiments, cetacean 28 may be detected andpositioned directly from the input data without requiring sophisticatedsignal processing techniques, such as beam forming, for exampleutilizing vector sensor technology.

System 10 may predict the survey energy (e.g., sound, acoustic) level ofpositions around the survey operation. For example, the estimated farfield signature of survey source 18 may be based on the measuredresponse of source receivers 26. A calibrated marine source may beutilized to produce the estimated far field signature based on themeasured source receivers 26 response. The calibrated marine source cancalculate the source signature in all directions. A propagation modelmay be used to determine the sound field at any point around theselected location (e.g., source 18). Sound propagation can be determinedusing different methods that solve the wave equation with given boundaryconditions. These methods include, without limitation, ray tracing, wavenumber integration techniques, normal modes, finite element methods, andother broadband modeling schemes.

Alternatively or in addition to the calculated far field signature,stored historical acquired high frequency survey source data may beutilized to predict acoustic fields (e.g., sound fields) across thesurvey operation. Referring to FIG. 1 several acoustic fields (e.g.,sound fields, acoustic zones, prevention zones) are illustrated by thehatched lines and are identified generally as 36 a, 36 b, 36 c, 36 d,etc. As previously noted, prevention zone 30 is identified by thenumeral 30 and it is also identified as a specific acoustic field 36 cin this embodiment. The output from this step may be a display ofcontour lines of sound/acoustic pressure levels at different distancesfrom survey source 18.

As will be further understood below, the acoustic fields may provide amore accurate determination for a prevention zone 30 than a generalgeometric determination. The acoustic fields provide a means ofproviding a real-time, or dynamic, prevention zone that may associatedwith the acoustic level (e.g., amplitude). For example, when conditionssuch as water depth and/or the survey source output signal are changedthe acoustic level encountered at various distances from the sourcechange. Thus, the protection provided by a mandated prevention zone of500 meter, for example, may be equally provided by a 250 meterprevention zone by changing the survey operation criteria. Thus,disruptions to the survey operations and exposure of the cetacean to thesurvey source may be mitigated. System 10 provides a means to makedecisions to maintain a geographic distance from the detected cetaceanas well as the functionality to adjust operational characteristics toavoid the undesired affects on the cetacean. For example, and withoutlimitation, system 10 may provide for determining and choosing analternative line for shooting to avoid the cetacean and/or changingshooting characteristics such as reducing and or changing the amplitudeand/or frequency emitted from source 18. In other words, by changing thesurvey parameters, such as the amplitude and/or frequency of the seismicsource the extent of the prevention zone may be altered, for example,reduced. One method for reducing the amplitude comprises turning off oneor more of the energy sources 18 during shooting. Limiting and/oravoiding contact of cetacean 28 and the prevention zone may compriselimiting the time of exposure such that the hearing loss, or equivalent,is limited or avoided.

System 10 may further include the determination and/or estimatedexposure of the identified and tracked cetacean 28 to survey source 18.For example, based on acoustic fields 36 and the course of cetacean 28and the time in which the cetacean was in each zone the exposure levelof cetacean 28 may be determined. This data may be utilized for longterm studies of effects on cetaceans as well as for dynamic control ofthe survey operations.

A monitoring system for marine mammal detection according to one or moreaspects of the present disclosure may include an array of receivers; anenergy source emitting a signal for conducting marine surveys; and aprocessing unit adapted to receive data from the array of receivers todetect a cetacean vocalization.

The processing unit may be adapted to determine a position of thedetected cetacean. The position may comprise a range from a selectedlocation and/or a direction from a selected location. The processingunit may continuously receive the data from the array of receivers. Theprocessing unit may periodically receive the data from the receivers,for example in association with activities such as activating, e.g.,shooting, the energy source. Shooting based recording and/or shot basedrecording, may also include long shots (e.g., greater than 20 seconds).The processing unit may detect the cetacean vocalization in a detectionsampling frequency. The detecting sampling frequency may be a highersampling frequency than a survey sampling frequency received by thearray of receivers for conducting a marine survey. The detectingsampling frequency may be lower than the survey sampling frequency. Insome embodiments, the ranges of the survey sampling frequency and thedetecting sampling frequency may overlap.

The array of receivers may comprise single sensor receivers. The arrayof receivers may comprise group formed single sensor receivers. Thesystem may comprise one or more group formed streamers. The array ofreceivers may include at least one selected from the group ofelectromagnetic sensors, hydrophones, geophones, accelerometers,pressure gradient sensors and particle motion sensors. The array ofreceivers may comprise a plurality of single sensor streamer receivers;and a plurality of single sensor source receivers, the source receiverspositioned proximate to the energy source.

A method for detecting marine mammals according to one or more aspectsof the present disclosure comprises deploying a plurality of receivers;recording data captured from the plurality of receivers; and detecting acetacean from the recorded data.

The method may comprise positioning the detected cetacean. Positioningmay include determining from a selected location at least one of a rangeto the detected cetacean or a direction of the detected cetacean. Thedetected cetacean may be positioned utilizing vector sensor technology.Positioning may comprise beam forming as well as other techniques andmethods.

The plurality of receivers may include single sensor receivers. Theplurality of receivers may comprise group formed receivers. The groupformed receivers may comprise at least one single sensor receiver.

The method may include conducting marine survey operations. For example,the method may comprise emitting a signal from an energy source;capturing reflections of the signal at the plurality of receivers; andutilizing the captured reflections for marine survey operations. Therecorded data may be continuously recorded or may be periodicallyrecorded, for example, in association with emitting the signal from theenergy source.

Detecting the cetacean may comprise identifying a vocalization of thecetacean. Identifying the vocalization may comprise monitoring adetection sampling frequency in the recorded data. The method mayinclude emitting a signal from the energy source; capturing reflectionsof the signal at the plurality of receivers; and utilizing the capturedreflections for marine survey operations. Utilizing the capturedreflections may comprise a survey sampling frequency. The detectionsampling frequency may be higher than the survey sampling frequencyaccording to one or more aspects of the present disclosure.

A method of conducting a marine survey according to one or more aspectsof the present disclosure comprises deploying a survey spread comprisinga plurality of receivers; receiving data from the plurality ofreceivers; detecting a cetacean from the received data; positioning thecetacean; emitting a signal from an energy source; and conducting amarine survey.

The plurality of receivers may comprise a group formed streamer. Theplurality of receivers may comprise single sensor receivers. Theplurality of receivers may comprise at least one selected from the groupof electromagnetic sensors, hydrophones, geophones, accelerometers,pressure gradient sensors and particle motion sensors.

The may further comprise tracking the movement of the detected cetacean.The method may comprise taking action limiting contact with the detectedcetacean. For example, limiting contact may comprise at least one ofaltering a course of the deployed survey spread, altering the emittedsignal's amplitude, and ceasing emitting the signal.

The method may comprise defining a prevention zone associated with thesurvey spread and a position of the detected cetacean. The preventionzone may be determined by legal regulation or according to other meansand criteria. The method may comprise defining an acoustic fieldrelative to the survey spread and correlating the position of thecetacean with the acoustic field. The acoustic field may be a preventionzone.

A monitoring system for marine mammal detection integrated into a marinesurvey system according to one or more aspects of the present disclosureincludes an array of receivers having a detecting sampling frequency; anacoustic source for emitting an acoustic signal for conducting marinesurveys; and a processing unit continuously receiving data in thedetection sampling frequency from the array of receivers, wherein theprocessing unit analyzes the received data and detects a cetaceanvocalization and determines a position of the cetacean.

A method for detecting marine mammals according to one or more aspectsof the preset disclosure includes providing a marine survey systemcomprising an array of receivers and an acoustic source, the array ofreceivers including a plurality of detection receivers; continuouslyrecording data from the plurality of detection receivers at a detectionsampling frequency; detecting vocalizations of a cetacean from thecontinuously recorded data; and determining a position of the cetacean.

An integrated marine survey and passive marine mammal detection systemaccording to one or more aspects of the present disclosure includes anarray of single sensor receivers having a detecting sampling frequencyand a survey sampling frequency; an acoustic source for emitting anacoustic signal for conducting a marine survey; and a processing unitcontinuously receiving data from the array of single sensor receivers inthe detecting sampling frequency, wherein the processing unit analyzesthe continuously received data and detects vocalizations of a cetacean.

A method of conducting a marine survey according to one or more aspectsof the present disclosure includes deploying a survey spread comprisingan array of single sensor receivers; continuously receiving data from aplurality of the single sensor receivers in a detection samplingfrequency; detecting a vocalization of a cetacean from the continuouslyreceived data in the detection sampling frequency; and determining aposition of the cetacean.

An embodiment according to one or more aspects of the present disclosureof a monitoring system for marine mammal detection integrated into amarine survey system includes an array of receivers; an energy sourceemitting a signal for conducting marine surveys; and a processing unitadapted to receive data from the array of receivers to detect a cetaceanvocalization.

The array of receivers may comprise a plurality of streamer receivers;and a plurality of source receivers, the source receivers associatedwith the energy source. The array of receivers may comprise singlesensor receivers. The array of receivers may comprise group formedsingle sensor receivers. The array of receivers comprise at least oneselected from the group of hydrophones, geophones, accelerometers,pressure gradient sensors, particle motion sensors and electromagneticsensors.

The processing unit continuously receives the data from the array ofreceivers. The data received from the array of receivers may beassociated with activation (e.g., shot) of the energy source. Theprocessing unit is adapted to determine a position of the detectedcetacean relative to a prevention zone.

The processing unit may be adapted to minimize contact of the detectedcetacean with the prevention zone. The prevention zone is associatedwith an acoustic level produced by the energy source.

An embodiment according to one or more aspects of the present disclosureof a method for limiting contact with marine mammals during marinesurvey operations comprises conducting a seismic survey; identifying aprevention zone relative to the seismic survey; detecting the presenceof a cetacean; and limiting contact with the prevention zone.

Identifying the prevention zone may comprise estimating an acousticlevel associated with the seismic survey. Estimating the acoustic levelmay comprise calculating the acoustic level of the seismic survey'semitted acoustic signal as a function of distance from the source of theemitted acoustic signal. Limiting contact may comprise at least oneselected from the group of altering the course of the seismic survey,reducing amplitude of the seismic survey's energy source and changing afrequency of the seismic survey's energy source.

Detecting may comprise positioning the cetacean. Positioning of thecetacean may include, without limitation, locating the cetacean relativeto a prevention zone, determining a range relative to a location and/ordetermining a direction relative to location. The method may includetracking the course of the detected cetacean.

The marine survey may comprise deploying plurality of receivers. Theplurality of receivers may comprise at least one selected from the groupof hydrophones, geophones, accelerometers, pressure gradient sensors,particle motion sensors and electromagnetic sensors. The plurality ofreceivers may comprise single sensor receivers and/or group formedsingle sensor receivers.

An embodiment according to one or more aspects of the present disclosurefor conducting a marine survey includes towing a survey spreadcomprising a plurality of receivers and an energy source along aselected course; emitting a signal from an energy source; receiving datafrom the plurality of receivers; detecting a cetacean from the receiveddata; positioning the detected cetacean; limiting contact with thedetected cetacean; and conducting a marine survey.

Limiting the contact may include minimizing exposure of the detectedcetacean to a prevention zone. A prevention zone may be associated withan acoustic level of the emitted signal. Limiting contact may comprise,without limitation, at least one selected from altering the selectedcourse and changing the signal emitted from the energy source. Changingthe signal emitted may include at least one of altering the frequency ofthe emitted signal and/or altering the amplitude of the emitted signal.

Although specific embodiments of the invention have been disclosedherein in some detail, this has been done solely for the purposes ofdescribing various features and aspects of the invention, and is notintended to be limiting with respect to the scope of the invention. Itis contemplated that various substitutions, alterations, and/ormodifications, including but not limited to those implementationvariations which may have been suggested herein, may be made to thedisclosed embodiments without departing from the spirit and scope of theinvention as defined by the appended claims which follow.

1. A method for limiting contact with cetaceans during marine surveyoperations, comprising: conducting a seismic survey comprising towing asurvey streamer having a plurality of streamer receivers along aselected course while receiving data from the plurality of streamerreceivers and while selectively emitting an acoustic signal from anenergy source, wherein the received data comprises a survey samplingfrequency associated with the emitted acoustic signal and a detectionsampling frequency; identifying a prevention zone; continuouslymonitoring the detection sampling frequency of the received data;detecting the presence of a cetacean while conducting the seismic surveyin response to continuously monitoring the detection sampling frequency;and limiting contact between the detected cetacean and the preventionzone.
 2. The method of claim 1, wherein the identifying the preventionzone comprises estimating an acoustic level associated with theconducting the seismic survey.
 3. The method of claim 2, wherein theestimating the acoustic level comprises calculating an acoustic level ofthe emitted acoustic signal as a function of distance from the energysource.
 4. The method of claim 1, wherein the limiting contact comprisesat least one selected from the group of altering the selected course ofthe seismic survey, reducing an amplitude of the emitted signal, andchanging a frequency of the emitted signal.
 5. The method of claim 1,wherein detecting comprises positioning the cetacean.
 6. The method ofclaim 1, further comprising tracking the course of the detectedcetacean.
 7. The method of claim 1, wherein the plurality of streamerreceivers comprise at least one selected from the group of hydrophones,geophones, accelerometers, pressure gradient sensors, particle motionsensors and electromagnetic sensors.
 8. The method of claim 1, whereinthe plurality of streamer receivers comprise single sensor receivers. 9.The method of claim 1, wherein the plurality of streamer receiverscomprise group formed single sensor receivers.
 10. The method of claim1, wherein the plurality of streamer receivers comprises a sourcereceiver.
 11. The method of claim 10, wherein the detection surveysampling frequency of the received data is obtained from the sourcereceiver.
 12. A method for conducting a marine survey, comprising:towing a survey spread comprising a plurality of streamer receivers andan energy source along a selected course; emitting a signal from theenergy source to produce reflections off of geological formations;receiving data from the plurality of streamer receivers comprising asurvey sampling frequency capturing the reflections of the emittedsignal; selecting from the plurality of towed streamer receivers anarray of streamer receivers for the purpose of detecting the presence ofcetaceans; receiving data from the selected array of streamer receiverscomprising a detection sampling frequency; detecting a cetaceanvocalization in response to monitoring the detection sampling frequencyof the received data; positioning the detected cetacean from thereceived data; and limiting contact with the detected cetacean ifnecessary in response to positioning the detected cetacean.
 13. Themethod of claim 12, wherein limiting contact comprises at least oneselected from altering the selected course and changing the signalemitted from the energy source.
 14. The method of claim 13, wherein thechanging the signal emitted comprises at least one of altering thefrequency of the emitted signal and altering the amplitude of theemitted signal.
 15. The method of claim 12, wherein the limiting thecontact comprises minimizing exposure of the detected cetacean to aprevention zone.
 16. The method of claim 15, wherein the prevention zoneis associated with an acoustic level of the emitted signal.
 17. Themethod of claim 16, wherein the limiting the contact comprises at leastone of altering the selected course and reducing the acoustic level. 18.The method of claim 12, wherein the plurality of streamer receiverscomprise at least one selected from the group of hydrophones, geophones,accelerometers, pressure gradient sensors, particle motion sensors andelectromagnetic sensors.
 19. The method of claim 12, wherein theplurality of streamer receivers comprises single sensor receivers. 20.The method of claim 12, wherein the plurality of streamer receiverscomprises group formed single sensor receivers.
 21. The method of claim12, further comprising tracking the location of the detected cetaceanwhile conducting the marine survey.
 22. The method of claim 12, whereinthe survey sampling frequency and the detection survey samplingfrequency comprise different frequencies.
 23. The method of claim 12,wherein the selected array of streamer receivers comprises sourcereceivers.